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Video streaming - is Qos the answer?

Kramerz132
Level 1
Level 1

We're having problem with a video stream we are distrubuting to a few users. Lately we got a lot of complaits regarding glitches/freezing in the video.

Hardware in 7600's: WS-X6704-10GE

Topology:

Incomming stream<<--port channel 2G Fiber-->>7600(SUP720)<<--10G fiber-->>7600(RSP720 SVI for video)<<--10G fiber-->> Switch<<-1G RJ45->>PC

- I've checked the interfaces on the 7600's but cant see any errors on the interfaces or output drops on the interfaces(no congestion?)

- We're seeing TX drops from the edge switch to the pc's. Investegating the cause with vendor. But my guess can be buffer problem going from 10G to 1G?

- We have not implemented any Qos on the 7600's however we have enabled qos to prioritize the video vlan on the edge switch.

- Peak traffic between 7600 and edge switch is about 1G(5min average)

- Would enabling QoS on the 7600 and do End to End Qos solve the problem? As far I understand qos will only help if the interface is congested which isn't the case here?

- What would be the best strategy for video streaming? Would the solution be to use the CBWFQ + LLQ  for this kind of traffic or  would LLQ starve the rest of the queue's?

Best Regards

2 Replies 2

Hello.

Could you provide the qos and port configuration + show interfaces" from edge switch (if not Cisco - try to replace with Cisco for clarity)?

LLQ is good if you limit the amount of traffic it may allocate on the interface.

PS: what is the video stream bandwidth and packet rate?

Joseph W. Doherty
Hall of Fame
Hall of Fame

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"We're seeing TX drops from the edge switch to the pc's. Investegating the cause with vendor. But my guess can be buffer problem going from 10G to 1G?"

Probably, and those drops could be the cause of your "...glitches/freezing in the video."

So, what you might want to first address is using QoS on egress edge ports to insure video traffic isn't dropped.

"...we have enabled qos to prioritize the video vlan on the edge switch."

Prioritized in what sense?  Dequeuing priority often makes little difference for typical buffers depths at gig or better bandwidths.  Priority avoiding drops, though, might be worthwhile.

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